Paleovegetation and paleoclimate in middle-late Pliocene, Shanxi, central China

Sequences of lacustrine sediments developed in intermontane basins in the middle-eastern Shanxi Plateau of China have been investigated in order to reconstruct the paleovegetation and paleoclimate for the middle-late Pliocene. According to the magnetostratigraphy and the fossil assemblages, the lacustrine sediments of Yushe and Taigu Basins were deposited between 5.5 and 2.5 Ma BP. The Zhangcun and Xiaobai Formations are considered to cover a similar period, ranging from 3.5 to 2.5 Ma BP. An increase of Picea and Abies shows that the climate began to become cold after about 4.4 Ma BP. A cold-wet episode, with relatively warm-dry and warm-humid intervals, occurred between 3.6 and 2.5 Ma BP in the Yushe and Taigu Basins. An increase Artemisia, Chenopodiaceae and Ephedra shows that the climate became drier after 2.5 Ma BP. The climate changes of this period probably reflect variations of the East Asian winter and summer monsoons, with an increase winter monsoon activity during the early Pleistocene.     

New Catarrhine fossils from Moroto II, Early Middle Miocene (ca 17.5 Ma) Uganda

During the 1998–2003 field seasons of the Uganda Palaeontology Expedition, dental remains of three catarrhine species were recovered from Moroto II, Uganda. Micromammals from the locality indicate a late Early Miocene to basal Middle Miocene (ca 17.5–17 Ma) age, younger than Rusinga (17.8 Ma), but similar in age to Buluk (17.2 Ma) and Kalodirr (17.2 Ma). This paper describes and interprets new catarrhines from the site, one of which is a victoriapithecid monkey, the second a new genus and species of small-bodied ape, and the third a large hominoid. A fourth species collected in the 1960's is attibuted to Afropithecus turkanensis. To cite this article: M. Pickford et al., C. R. Palevol 2 (2003).     

Centennial-scale climate variability in the Timor Sea during Marine Isotope Stage 3

We present a high-resolution ( 60–110 yr) multi-proxy record spanning Marine Isotope Stage 3 from IMAGES Core MD01-2378 (13°04.95′ S and 121°47.27′ E, 1783 m water depth), located in the Timor Sea, off NW Australia. Today, this area is influenced by the Intertropical Convergence Zone, which drives monsoonal winds during austral summer and by the main outflow of the Indonesian Throughflow, which represents a key component of the global thermohaline circulation system. Thus, this core is ideally situated to monitor the linkages between tropical and high latitude climate variability. Benthic δ¹⁸O data (Planulina wuellerstorfi) clearly reflect Antarctic warm events (A1–A4) as recorded by the EPICA Byrd and Dronning Maud Land ice cores. This southern high latitude signal is transferred by deep and intermediate water masses flowing northward from the Southern Ocean into the Indian Ocean. Planktonic δ¹⁸O shows closer affinity to northern high latitudes planktonic and ice core records, although only the longer-lasting Dansgaard–Oeschger warm events, 8, 12, 14, and 16–17 are clearly expressed in our record. This northern high latitude signal in the surface water is probably transmitted through atmospheric teleconnections and coupling of the Asian–Australian monsoon systems. Benthic foraminiferal census counts suggest a coupling of Antarctic cooling with carbon flux patterns in the Timor Sea. We relate increasing abundances of carbon-flux sensitive species at 38–45 ka to the northeastward migration of the West Australian Current frontal area. This water mass reorganization is also supported by concurrent decreases in Mg/Ca and planktonic δ¹⁸O values (Globigerinoides ruber white).     

Indications for a humid climate in the Western Desert of Egypt 11–10 Myr ago: evidence from Galagidae (Primates, Mammalia)

The timing of desertification of the Sahara Desert is poorly understood, with recent estimates indicating an onset of hyper-aridity during the Latest Miocene. Field work in Egypt in 2005 has led to the discovery of evidence that indicates that 11–10 Ma the Western Desert was covered in woodland. Fossiliferous cave breccia at Sheikh Abdallah, Western Desert, Egypt, has yielded a Late Miocene (11–10 Ma) microvertebrate fauna, which contains Galagidae, Microchiroptera, Macroscelididae, Soricidae, Erinaceidae, and Rodentia. The locality also yielded the remains of frogs, snakes, lizards, and birds. The fauna indicates a mean annual rainfall in excess of 500 mm and perhaps as much as 1,200 mm. This palaeoclimatic information is important because it reveals that the Sahara Desert, which is today the largest in the world, was either considerably smaller during the Late Miocene than it is today, or that it did not yet exist as a continuous hyper-arid belt right across the continent. This data accords with estimates of a Latest Miocene (8–7 Ma) increase in aridity in the Sahara. To cite this article: M. Pickford et al., C. R. Palevol 5 (2006).     

The late Pleistocene climates of the Lake Zeribar region (Kurdistan,western Iran) deduced from the ecology and pollen production of nonarboreal vegetation

The concept of an arid pleniglacial in the Middle East depends primarily on the interpretation of pollen diagrams including those of Lake Zeribar in the Zagros Mountains of western Iran. It has been assumed that Lake Zeribar was surrounded by a Chenopodiaceae-Artemisia steppe and that the climate was therefore dry. Both assumptions are questioned. The environment of Pleistocene Lake Zeribar may have been similar to the tragacanthic or alpine zone of the modern Zagros Mountains. The dominance by pollen of Chenopodiaceae and Artemisia is explained by low pollen production of high-altitude vegetation, preferential incorporation of pollen of late-blooming plants into the sediments, and high production and long-distance transport of lowland pollen. In any case, high percentages of Chenopodiaceae and Artemisia pollen do not necessarily indicate low annual precipitation but a highly seasonal climate with cold winters and hot, dry summers. Such a climatic regime was in effect continuous except for a period beginning about 10600 B. P. during which summer rainfall or reduced summer drought occurred. This change in seasonality resulted in the dominance of Poaceae pollen and the initial increase in arboreal pollen. A moisture curve based on the ratio between Chenopodiaceae and Artemisia pollen indicates a pleniglacial climate with wet winters and a late-glacial and early-Holocene climate with periods of intense aridity. The climatic history presented here is compatible with non-palynological evidence of regional late Pleistocene climates and with seasonality changes suggested by climatic modelling based on orbital parameters.Abbreviations C/A Chenopodiaceae-Artemisia ratio     

Late Neogene planktonic foraminifera of the Cibao Valley (northern Dominican Republic): Biostratigraphy and paleoceanography

An assemblage of planktonic foraminifera is described from 125 samples taken from the Cercado, Gurabo, and Mao Formations in the Cibao Valley, northern Dominican Republic. The primary objectives of this study are to establish a biochronologic model for the late Neogene of the Dominican Republic and to examine sea surface conditions within the Cibao Basin during this interval. The Cercado Formation is loosely confined to Zones N17 and N18 ( 7.0–5.9 Ma). The Gurabo Formation spans Zones N18 and N19 ( 5.9–4.5 Ma). The Mao Formation is placed in Zone N19 ( 4.5–3.6 Ma). Changes in the relative abundances of indicator species are used to reconstruct sea surface conditions within the basin. Increasing relative abundances of Globigerinoides sacculifer and Globigerinoides ruber, in conjunction with a decreasing relative abundance of Globigerina bulloides, suggests the onset of increasing sea surface temperature and salinity in conjunction with diminishing primary productivity at 6.0 Ma. Abrupt increases in the relative abundances of G. sacculifer and G. ruber at 4.8 Ma suggest a major increase in sea surface temperature and salinity in the early Pliocene. The most likely mechanism for these changes is isolation of the Caribbean Ocean through progressive restriction of Pacific–Caribbean transfer via the Central American Seaway. Periods of high productivity associated with upwelling events are recorded in the upper Cercado Formation ( 6.1 Ma) and in the middle Mao Formation ( 4.2 Ma) by spikes in G. bulloides and Neogloboquadrina spp. respectively. The timing of major increases in sea surface salinity and temperature as well as decreasing productivity ( 4.8 Ma) and periods of upwelling ( 6.1and 4.2 Ma) in the Cibao Basin generally corroborate previously suggested Caribbean oceanographic changes related to the uplift of Panama. Changes in sea surface conditions depicted by paleobiogeographic distributions in the Cibao Basin suggest that shoaling along the Isthmus of Panama had implications in a shallow Caribbean basin as early as 6.0 Ma. Major paleobiologic changes between 4.8 and 4.2 Ma likely represent the period of final closure of the CAS and a nearly complete disconnection between Pacific and Caribbean water masses. This study illustrates the use of planktonic foraminifera in establishing some paleoceanographic conditions (salinity, temperature, productivity, and upwelling) within a shallow water basin, outlining the connection between regional and localized oceanographic changes.     

The Middle Miocene climatic transition in the Southern Ocean: Evidence of paleoclimatic and hydrographic changes at Kerguelen plateau from planktonic foraminifers and stable isotopes

Middle Miocene (14.8–11.9 Ma) deep-sea sediments from ODP Hole 747A (Kerguelen Plateau, southern Indian Ocean) contain abundant, well-preserved and diverse planktonic foraminiferal assemblages. A detailed study of the climatic and hydrographic changes that occurred in this region during the Middle Miocene Climatic Transition led to the identification of an intense cooling phase (the Middle Miocene Shift). Abundance fluctuations of planktonic foraminiferal species with different paleoclimatic affinities, and oxygen and carbon stable isotopes have been integrated in a multi-proxy approach. Reconstruction of changes in foraminiferal faunal composition and diversity through time were the basis for identification of three foraminiferal biofacies. The most prominent faunal change took place at 13.8 Ma, when a fauna with warm-water affinity (marked by high abundance of Globorotalia miozea group and Globoturborotalita woodi plexus) was replaced by an oligotypic, opportunistic fauna with typical polar characters and dominated by neogloboquadrinids. This faunal change is interpreted as the result of foraminiferal migration from adjacent bioprovinces, caused by modifications in climate and hydrography. A positive 2.0‰ shift in δ¹⁸O (interpreted as the Mi3 event) and a related positive 1.0‰ shift in δ¹³C (corresponding to the CM6 event) accompanied this faunal turnover. These are interpreted to reflect substantial reorganization of Southern Ocean waters, the northward migration of the Polar Front and a strong increase in primary productivity. The second faunal change took place at 12.9 Ma and was characterized by the gradual decrease in abundance of the neogloboquadrinids and the recovery of Globorotalia praescitula/scitula group and Globigerinita glutinata. A positive 1.5‰ shift in δ¹⁸O (interpreted as the Mi4 event) and a concurrent gradual negative shift in δ¹³C accompanied this faunal change, witnessing further modifications of the climate/ocean system. Variations in sea surface temperature, considered as the main factor causing changes of surface hydrography at the Kerguelen Plateau, seem to have been driven by obliquity and long-term eccentricity, thus suggesting a key role played by the astronomical forcing on the evolution of Southern Ocean dynamics during the Middle Miocene. Also an evident 1.2 Myr modulation of the δ¹³C record suggests a main control of the long-term obliquity cycles on the carbon cycle dynamics. Particularly, the Mi3/CM6 events exactly fit with a node of the 1.2 Myr modulation cycles. This confirms the key role played by orbital parameters on high-latitude temperatures and Antarctic ice volume, and indirectly on global carbon burial and/or productivity. This climatic transition was marked also by changes in surface hydrography. From 14.8 to 13.8 Ma an intermediate-strength thermocline controlled by seasonality developed just below the photic zone. Weaker seasonality characterized the interval from 13.8 to 12.9 Ma, when the thermocline became shallower and sharper and favored intermediate-water foraminifers. From 12.9 Ma, seasonality increased again and an intermediate-strength thermocline re-developed.     

Globorotalia puncticulata: Population divergence, dispersal and extinction related to Pliocene–Quaternary water masses

The isolating effect of water mass partitioning of populations on the morphology, stratigraphic distribution and extinction of planktonic foraminifera is assessed from the Pliocene–Quaternary record of Globorotalia puncticulata. Southern Hemisphere, Mediterranean and North Atlantic data on these aspects of its history are examined and appear consistent with a limited dispersal biogeographic model wherein populations are largely confined by hydrographic barriers.Earliest populations appeared during the latest Miocene in Southern Hemisphere middle latitude water masses. However, morphometric analysis shows that significant differentiation in the axial shape of shells had developed by 4 Ma between Southwest Pacific populations from ODP Site 1123 (temperate water) and ODP Site 1119 (subantarctic water). These sites are in close proximity but separated by the Subtropical Front. At Site 1123 inflation of late-formed chambers and reduction in the number included in the outer whorl created shell profiles that anticipated the globose form of Globorotalia inflata. The latter's gradual evolution from G. puncticulata s.s. took place in this temperate water mass, with the earliest morphotypes with three chambers in the outer whorl present by 4.1 Ma. In contrast, subantarctic populations at Site 1119 retained four chambers but their axial shape was modified. The development of a large, highly arched aperture and increase in the number of chambers in the outer whorl in Mediterranean–North Atlantic Globorotalia puncticulata bononiensis is an example of population differentiation later in the Pliocene.Chronostratigraphy shows that the northward expansion of central temperate water populations commenced with their occupation of Southwest Pacific subtropical water about 4.8 Ma. The rather abrupt entry of substantial populations into Mediterranean and North Atlantic water at 4.5 Ma marked a major biogeographic expansion and established G. puncticulata as a bipolar species. It was widely distributed about 3 Ma, with major populations in several water masses during a period of middle Pliocene warmth.After this acme North Atlantic and Mediterranean G. puncticulata bononiensis populations collapsed as late Pliocene Northern Hemisphere glacials intensified. They were extinguished in MIS 96 (2.4 Ma). Concurrently, G. puncticulata s.s became extinct in the warm subtropical Southwest Pacific. Subantarctic populations persisted but in turn were decimated in severe glacials during the Middle Pleistocene Transition. Most had disappeared by MIS 16 (0.66 Ma). However, at Sites 594 and 1119 there was a small Lazarus-like revival in MIS 11 (0.41 Ma). The highest known occurrence is in MIS 9 (0.33 Ma) at Site 1119. Confinement of the species to subantarctic water in the Pleistocene may have raised its vulnerability to extinction.While stable isotope data indicate that the lineage's evolution is related to depth habitat selection about the thermocline, its biogeography suggests that hydrographic barriers significantly isolated populations and probably facilitated speciation. Eddies such as the North Brazil Current rings provide conduits for inter-water mass transfer of populations but the history of G. puncticulata suggests that such mechanisms seldom operated successfully.The morphology of the lectotype of G. puncticulata s.s., from beach sand at Rimini, Italy, is consistent with a lower Pliocene source. Reports of living occurrences are poorly documented and the species is considered to be extinct.     

Sea ice seasonality during the Holocene, Adélie Land, East Antarctica

Thin sections of laminated cores from different Antarctic coastal areas have demonstrated the potential of diatom species to document climate change at the seasonal scale. Here we present the relative abundances of four diatom species and species groups (Fragilariopsis curta group as a proxy for yearly sea ice cover, F. kerguelensis as a proxy for summer sea-surface temperature, Chaetoceros Hyalochaete resting spores as a proxy for spring sea ice melting and the Thalassiosira antarctica group as a proxy for autumn sea ice formation) in core MD03-2601 retrieved off Adélie Land on the Antarctic continental shelf. These abundances were compared to surface temperatures and sea ice cover modelled over the last 9000 years. Both the marine records and the simulated climate demonstrated a cooler Early Holocene (9000–7700 years BP), a warmer Mid-Holocene (7700–4000 years BP) and a colder Late Holocene (4000–1000 years BP). Yearly sea ice cover followed an inverse pattern to temperatures with less sea ice during the Mid-Holocene Hypsithermal than during the Late Holocene Neoglacial. However, diatom census counts and model output indicate that sea ice spring melting happened earlier in the season, as expected, but that autumn sea ice formation also occurred earlier in the season during the Hypsithermal than during the colder Neoglacial, thereby following seasonal changes in local insolation.     

Establishment of the western Pacific warm pool during the Pliocene: Evidence from planktic foraminifera, oxygen isotopes, and Mg/Ca ratios

This study presents new evidence of when and how the Western Pacific Warm Pool (WPWP) was established in its present form. We analyzed planktic foraminifera, oxygen isotopes, and Mg/Ca ratios in upper Miocene through Pleistocene sediments collected at Deep Sea Drilling Program (DSDP) Site 292. These data were then compared with those reported from Ocean Drilling Program (ODP) Site 806. Both drilling sites are located in the western Pacific Ocean. DSDP Site 292 is located in the northern margin of the modern WPWP and ODP Site 806 near the center of the WPWP. Three stages of development in surface-water conditions are identified in the region using planktic foraminferal data. During the initial stage, from 8.5 to 4.4 Ma, Site 806 was overlain by warm surface water but Site 292 was not, as indicated by the differences in faunal compositions and sea-surface temperature (SST) between the two sites. In addition, the vertical thermal gradient at Site 292 was weak during this period, as indicated by the small differences in the δ¹⁸O values between Globigerinoides sacculifer and Pulleniatina spp. During stage two, from 4.4 to 3.6 Ma, the SST at Site 292 rapidly increased to 27 °C, but the vertical thermal gradient had not yet be strengthened, as shown by Mg/Ca ratios and the presence of both mixed-layer dwellers and thermocline dwellers. Finally, a warm mixed layer with a high SST ca. 28 °C and a strong vertical thermal gradient were established at Site 292 by 3.6 Ma. This event is marked by the dominance of mixed-layer dwellers, a high and stable SST, and a larger differences in the δ¹⁸O values between G. sacculifer and Pulleniatina spp. Thus, evidence of surface-water evolution in the western Pacific suggests that Site 292 came under the influence of the WPWP at 3.6 Ma. The northward expansion of the WPWP from 4.4 to 3.6 Ma and the establishment of the modern WPWP by 3.6 Ma appear to be closely related to the closure of the Indonesian and Central American seaways.     

Holocene altitudinal shifts in vegetation belts and environmental changes in the Sierra Madre Occidental, Northwestern Mexico, based on modern and fossil pollen data

A modern pollen rain study was performed in a 300 km-long altitudinal transect (~ 28° N latitude) from 300 to 2300 m elevation. The higher elevation modern communities: epithermal oak–pines, pine–oak forest, pine forest, and mixed conifer forest were easy to distinguish from their pollen content. In contrast, lower elevation subtropical communities: thornscrub and tropical deciduous forest were difficult to separate, because they share many pollen taxa. Nevertheless we identify high frequencies of Bursera laxiflora as an important component of the tropical deciduous forest.Additionally, fossil pollen was analyzed at three sites located between 1700 and 1950 m altitude at ~ 28° latitude north in the Sierra Madre Occidental of northwestern Mexico. The sites were in pine–oak (Pinus–Quercus), pine, and mixed-conifer forests respectively. Shifts in the altitudinal distribution of vegetation belts were recorded for the last 12,849 cal yr BP, and climate changes were inferred. The lowest site (pine–oak forest) was surrounded by pine forest between 12,849 and 11,900 cal yr BP, suggesting a cold and relatively dry Younger Dryas period. The early Holocene was also cold but wetter, with mixed conifer forest with Abies (fir) growing at the same site, at 1700 m elevation, 300 m lower than today. After 9200 cal yr BP, a change to warmer/drier conditions caused fir migration to higher elevations and the expansion of Quercus at 1700 m. At 5600 cal yr BP Abies was growing above 1800 m and Picea (spruce) that is absent today, was recorded at 1950 m elevation. Fir and spruce disappeared from the 1950 m site and reached their present distribution (scattered, above 2000 m) after 1000 cal yr BP; we infer an episodic Holocene migration rate to higher elevations for Abies of 23.8 m/1000 cal yr and for Picea of 39.2 m/1000 cal yr. The late Holocene reflects frequent climate oscillations, with variations in the representation of forest trees. A tendency towards an openness of the forest is recorded for the last 2000 yrs, possibly reflecting human activities along with short-term climate change.     

First results from satellite-linked archival tagging of porbeagle shark, Lamna nasus: Area fidelity, wider-scale movements and plasticity in diel depth changes

Understanding the habitat preferences of large marine vertebrates has only recently become tractable with the widespread availability of satellite telemetry for monitoring movements and behaviour. For many species with low population abundances, however, little progress has been made in identifying space use patterns. The endothermic porbeagle shark, Lamna nasus, has declined in the North Atlantic due to severe fishing pressure, with little evidence of recovery. One potential factor exacerbating population decline is area fidelity to coastal waters where fisheries are intensive. We tested for short-term area fidelity by attaching pop-up satellite-linked archival transmitters to four porbeagles in summer 2007, resulting in 175 days total tracking time covering an estimated 10,256 km distance. Throughout July and August the sharks occupied localised areas (8,602 – 90,153 km²) within the Celtic Sea, between the south-west UK, south-west Wales and southern Ireland. Only one shark was tracked into the autumn, when it moved into deep water off the continental shelf, then north towards colder latitudes. Sharks occupied a broad vertical depth range (0 – 552 m) and water temperatures (9° - 19 °C). Dives were made frequently from the surface to near the seabed in shelf areas, however, in shelf edge habitats extended periods of time were spent at depths > 300 m. Porbeagles showed considerable plasticity in diel depth changes within and between individuals and as a function of habitat type. In addition to no obvious day-night difference in depth occupation, some sharks showed reverse diel vertical migration (DVM) (dawn ascent – dusk descent) in well-mixed coastal waters whereas normal DVM (dawn descent – dusk ascent) characterised movements into deeper, thermally well-stratified waters. The variable behaviours may reflect the need for different search strategies depending on habitat and prey types encountered. These results show porbeagles are potentially vulnerable to fisheries throughout the summer when they aggregate, and that large scale movement across national boundaries identifies the need for international conservation measures.     

Reconstruction of Indian monsoon variability over the past 230,000 years: Planktic foraminiferal evidence from the NW Arabian Sea open-ocean upwelling area

We determined the faunal composition and total number of tests (#/g) of planktic foraminifera (> 125 μm) in core KH00-05 GOA 6 near Oman in order to decipher monsoon-induced variability of oceanographic productivity in the open-ocean upwelling area in the northwest Arabian Sea. The core contains a continuous record of sedimentation over the last 230 kyr, with the age model based on oxygen isotope and accelerator mass spectrometry ¹⁴C dates. We focused on species (Globigerina bulloides and Globigerinita glutinata) typical for SW monsoonal upwelling and species typical for NE monsoon conditions (Neogloboquadrina incompta, Neogloboquadrina dutertrei, Globigerinoides ruber, and Globigerinoides sacculifer). The changes in relative abundance of these monsoonal indicators suggest that the open-ocean upwelling area was dominated by the SW monsoon during interglacial periods, but by the NE monsoon during glacial periods.Increases in total test abundance during glacial periods confirmed that the NE monsoon rather than SW monsoon contributes largely to planktic foraminiferal productivity in this area. We argue that three types of circumstances resulted in high productivity, with nine high productivity events occurring at a 23-kyr frequency. The first type caused high productivity events at 102 and 199 ka (interglacial periods), characterized by the dominance of upwelling species, indicating high productivity during strong SW monsoons, correlated with high July insolation at 45° N. An exceptional high productivity event occurred at 37 ka during interglacial marine isotope stage (MIS) 3, with contributions from both SW and NE monsoons. The second type of high productivity event occurred at 61, 147, and 175 ka, during glacial periods, characterized by dominance of NE monsoon species, and correlated with low January insolation at 45° N. In addition, a high productivity event at 85 ka (interglacial period) also was induced by enhanced NE monsoons. The last two high productivity events occurred during transitional periods from glacial to interglacial (MIS 6/5.5 and 2/1), were characterized by the replacement of NE monsoon species with upwelling species, and corresponded to abrupt climate warming, suggesting that they are related to both accelerated SW monsoon systems and reduced NE monsoon systems.     

Synthesis, structural analysis and anticonvulsant activity of a ternary Cu(II) mononuclear complex containing 1,10-phenanthroline and the leading antiepileptic drug valproic acid

The synthesis and characterization of the binary complex of copper(II) with the antiepileptic drug valproic acid sodium salt (Valp) and the related ternary complex with 1,10-phenanthroline (phen) are reported, as well as the anticonvulsant properties of the latter. The characterization was carried out by means of elemental analyses, infrared (IR), UV–visible (UV–vis) spectrophotometry and Electron Paramagnetic Resonance (EPR). The X-ray crystal structure of the mononuclear complex bis(2-propylpentanoate)(1,10-phenanthroline)copper(II) [Cu(Valp)₂phen] is showed for the first time. It crystallized in C2/c space group with unit cell dimensions of a = 14.939(1) Å, b = 19.280(1) Å, c = 9.726(1) Å, β = 97.27(2)°, V = 2778.8(4) Å ³ and Z = 8. The carboxylates bond in an asymmetric chelating mode and the copper atom adopts a highly distorted octahedral coordination, characterized by the sum of the angles of 365.9° around Cu(II) and its nearest atoms in the CuN₂O₂ + O₂ chromophore instead of the expected 360° for a basal square planar geometry found in most Cu(II) complexes. Molecules assemble three by three through slipped π–π stacking of the aromatic phen with respectively 3.519 and 3.527 Å distances, in a head-to-tail arrangement. Studies of the anticonvulsant properties of this bioligand chelate evidenced its lack of efficacy in preventing MES-induced seizures. Interestingly, complex 4 protected mice against the Minimal Clonic seizures at doses that do not cause Rotorod toxicity, with an ED₅₀ documenting very potent anticonvulsant activity in this model of seizure, a particularly useful pharmacological profile of activity for the treatment of Petit Mal seizures.     

Trace fossils of the arthropod Camptophyllia from the Westphalian (Carboniferous) rocks of Lancashire, UK and their palaeoenvironmental context

Two arthropod trace fossils are described and analysed from the Carboniferous Lower Westphalian (C. communis and basal A. modiolaris chronozones) coal-bearing strata of Lancashire. The biserial trackway Diplichnites triassicus consists of five overlapping en echelon sets of 7–9 tracks preserved as epichnia and hypichnia in lacustrine siltstones. The trackway suggests subaqueous in-phase walking by a multi-segmented producer with a body length of 35–40 mm, width 17–22 mm, and 7–9 appendages. Curved, clustered, or laterally repeated, hypichnial lobes with transverse striations on the base of ripple cross-laminated sandstone are identified as Rusophycus versans. This trace fossil is interpreted as shallow resting or furrowing burrows of a homopodous arthropod, 30–60 mm long, 15–30 mm wide, and probably the same kind of arthropod as produced D. triassicus.A review of contemporary arthropod body fossils from Lagerstätten in Lancashire favours the onisciform, or Arthropleura like arthropod Camptophyllia as a potential producer of both of these trace fossils in a lacustrine palaeoenvironment.This study integrates the analysis of sediments, trace fossils and body fossils for reconstructing the arthropod biota and ecology in Westphalian lacustrine and crevasse splay fluvial palaeoenvironments.     

Maximal oxygen uptake, maximal voluntary isometric contraction and physical activity in young Danish adults

In a randomly selected sample of 88 men and 115 women, aged 23–27 years from Denmark, maximal oxygen uptake ( O_2max), maximal voluntary isometric contraction (MVC) in four muscle groups and physical activity were studied. The O_2max was 48.0 ml · min^–1 kg^–1 and 39.6 ml · min^–1 · kg^–1 for the men and the women, respectively. The MVC was 10% lower than in a comparable group of Danes of the same age and height studied 35 years ago. Only in men was sports activity directly related to O_2max (ml · min^–1 · kg^–1; r=0.31, P<0.01). The MVC of the knee extensors was related to O_2max in the men (r=0.31, P<0.01), but there was no relationship between the other measurements of MVC and O_2max. In the women O_2max (ml · min^–1 · kg^–1) was only related to body size, i.e. body mass index, percentage body fat and body mass [(r= –0.47, –0.48 (both P<0.001) and –0.34. (P<0.01), respectively)]. There were differences in O_2max in the men, according to education and occupation. Blue collar workers and subjects attending vocational or trade schools in 1983 had lower O_2max and more of them were physically inactive. In the women differences were also found, but there was no clear pattern among the groups. More of the women participated regularly in sports activity, but more of the men were very active compared to the women.     

Elevated spring temperature stimulates growth, but not smolt development, in anadromous Arctic charr

Parr–smolt transformation and growth were studied in captive offspring of anadromous Arctic charr (Salvelinus alpinus) from the Hals watercourse in northern Norway (70°N), held either at a natural temperature (< 1 °C until May) or at a temperature elevated to 6 °C in late March. In mid-May, 5 weeks after the increase in photoperiod from 8:16 h light:dark to continuous light, gill Na⁺, K⁺-ATPase activity started to increase in both temperature groups, concurrent with the final development of full seawater tolerance. Temperature had no effect on the development of gill Na⁺, K⁺-ATPase activity, or on hypoosmoregulatory ability. The fish in both treatments resumed growth in mid-May, but from then on growth was faster in the elevated than in the ambient temperature group. In the former group, fish mass doubled in 6 weeks (from 65 to 137 g), and growth ceased at the time when the fish were about to complete their parr–smolt transformation. These findings show that an early vernal temperature increase advances the seasonal growth cycle, but not the parr–smolt transformation, in anadromous Arctic charr.     

Evidence of increasing surface water oligotrophy during the Campanian–Maastrichtian boundary interval: Calcareous nannofossils from DSDP Hole 390A (Blake Nose)

The latest Cretaceous (Campanian–Maastrichtian) is characterized by several global cooling and intermittent warming events. These climatic changes influenced the palaeoceanography substantially, including changes of the deep water sources and surface water currents. One of the most prominent episodes of climatic cooling occurred during the Campanian–Maastrichtian transition. This study focuses on the palaeoclimate and palaeoceanography of the Campanian–Maastrichtian transition by analysing the calcareous nannofossils of DSDP Hole 390A (139.92–126.15 mbsf; Blake Nose). For the examination of calcareous nannofossils sixty samples were processed using the settling technique. Biostratigraphical index taxa (Broinsonia parca constricta, Uniplanarius trifidus, and Tranolithus orionatus) suggest a late Campanian age for the major part of the studied section. The calcareous nannofossils are well preserved, highly abundant (6.80 billion specimens/gram sediment) and diverse (80 species/sample). The assemblages are dominated by Prediscosphaera spp. (20.5%), Watznaueria spp. (20.3%) and Retecapsa spp. (9.8%). Cool water taxa (Ahmuellerella octoradiata, Gartnerago segmentatum, and Kamptnerius magnificus), however, appear less frequently and do not exceed more than 1%. Due to their rarity these cool water taxa do not support the existence of an intense cooling phase during the Campanian–Maastrichtian transition at DSDP Hole 390A. Around 133 mbsf several nannofossil taxa, however, show a distinctive turnover. Mesotrophic species like Discorhabdus ignotus, Zeugrhabdotus bicrescenticus and Zygodiscus exmouthiensis are abundant below 133 mbsf, whereas oligotrophic taxa like Watznaueria spp., Eiffellithus spp. and Staurolithites flavus become common above this level. These changes imply a decrease in the input of nutrients, perhaps caused by a reorganization of ocean currents (Palaeo Gulf Stream) and reduced upwelling.     

Arabia–Eurasia collision and the forcing of mid-Cenozoic global cooling

The end of the Eocene greenhouse world was the most dramatic phase in the long-term cooling trend of the Cenozoic Era. Here we show that the Arabia–Eurasia collision and the closure of the Tethys ocean gateway began in the Late Eocene at ~ 35 Ma, up to 25 million years earlier than in many reconstructions. We suggest that global cooling was forced by processes associated with the initial collision that reduced atmospheric CO₂. These are: 1) waning volcanism across southwest Asia; 2) increased organic carbon storage in Paratethyan basins (e.g. Black Sea and South Caspian); 3) increased silicate weathering in the collision zone and, 4) a shift towards modern patterns of ocean currents, associated with increased vigour in circulation and organic productivity.     

Lateglacial climate development in NW Romania — Comparative results from three quantitative pollen-based methods

This paper provides quantitative reconstructions of the Lateglacial changes in four climate parameters from two fine-resolution pollen profiles in the Gutaiului Mountains, NW Romania. Climate estimates are based on two modern analogue techniques (with and without considering vegetation types) and weighted averaging partial least squares regression (WA-PLS), giving evidence for several climatic fluctuations during the period from > 14,700 to 11,500 cal. yr BP. The comparative results of the two modern analogue techniques show consistent trends of climate changes that are also coherent at both sites, but these results appear to largely disagree compared with climate reconstruction provided by WA-PLS.The modern analogue techniques revealed four intervals with low temperatures: prior to 14,700 cal. yr BP, between 13,950 and 13,800; 13,400 and 13,200; and 12,700 and 11,700 cal. yr BP. The temperature declines were more pronounced for winter than for summer, suggesting an intensification of seasonality, which together with a drop in precipitation indicates an increase in continentality. The Younger Dryas is the most pronounced cooling phase with winter temperatures ~ 14–16 °C colder than modern conditions, annual and summer temperatures ~ 2–5 °C and ~ 2 °C, respectively below present ones. Precipitation was ~ 400–500 mm, half that of present. During the Bølling and Allerød, summer temperatures were close to modern values (13 to 17 °C), whereas winter (− 6 to − 12 °C) and annual temperatures (0.5 to 6 °C) as well as precipitation were (550 to 700 mm) lower, indicating more continental conditions compared to the present-day climate.